Semester

Spring

Date of Graduation

2020

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Scott Bowdridge

Committee Member

Scott Greiner

Committee Member

Domingo Matta-Padrino

Abstract

Improvement of lamb performance in low-input operations may prove vital for the sustainability of eastern US sheep production. Maintaining growth while improving carcass conformation using terminal sire crossbreeding systems may increase value in a pasture-based system. Therefore, the aim of this study was to compare effects of terminal sire breed on parasitism, growth, marketability of grazing lambs. Suffolk (SU; n = 2) and Texel (TX; n = 2) sires were mated to commercial ewes at the WVU Organic Farm. April-born lambs were managed on pasture as one group until weaning (mid-June), then were separated into 3 replicates per sire breed. Lambs were rotationally grazed for 93-d with paddock movement every 10-d and supplemented at a rate of 2% (16% CP) bodyweight. Weights were collected at weaning and then weekly for the duration of the study. Fecal egg counts (FEC) and FAMACHA scores were collected bi-weekly. Ultrasound measures of ribeye area (REA) were obtained at study conclusion and lambs were marketed at a graded auction. Sire breed did not impact weaning weight or growth rate. However, TX-sired lambs required fewer deworming treatments than SU-sired lambs (39% vs. 12%; P < 0.01). FAMACHA scores were numerically lower in TX vs. SU-sired lambs (1.58 vs. 1.96; P < 0.01. Texel-sired lambs had greater REA (11.57 vs 9.42 cm2; P < 0.01) and graded better at auction. Texel-sired lambs sold for $27/cwt. more than Suffolk-sired lambs. These data demonstrate that the desirable composition of TX-sired lambs translated into greater market value.

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